Your play was fine, of course. JJ should not be the weakest hand you push. You pushed a top 3% hand. When you get your money in as a 2:1 favorite, sometimes you are going to lose. This doesn't mean there is anything safer to do. You are simply going to bust out of a lot of tournaments.
I guess ive been on a downswing since i started, but i dont think i know what a downswing is yet.
Right, most people don't know what a downswing looks like. It's not a downward trend or a graph which looks like someone climbed a mountain and then fell off the other side. The following graph shows a real downswing from a professional SNG player who grinds $16 SNGs:

try to catch downswing ( but with +ev ) in sng's before playing some serious for you mtt. Thats the trick. GL
Cards have no memory. They don't owe you anything. Just make the right decision in each situation, and you will reach the long run eventually, where poker looks like a game of chess for $10k with a coin flip for $1k. At that point you can be quite unlucky, and yet still be far ahead.